Training memory without aversion: Appetitive hole-board spatial learning increases adult hippocampal neurogenesis

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Neuroplasticity

Background:

• Adult hippocampal neurogenesis (AHN) is modulated by learning experiences.
• Most studies use aversive tasks (e.g., water maze), introducing stress as a confounder.
• The effects of appetitive learning on AHN remain largely unknown.

Purpose of the Study:

• To investigate how appetitive spatial learning in a hole-board maze affects AHN (cell proliferation, immature neurons).
• To examine the impact on hippocampal neuroplasticity markers (BDNF, IGF-II, CREB phosphorylation).
• To establish a paradigm for studying AHN and plasticity while minimizing aversive variables.

Main Methods:

• Mice were trained in a food-rewarded hole-board maze (Trained), exposed to a non-learning version (Pseudotrained), or a no-reward control (Control).
• Assessed spatial reference and working memory performance.
• Quantified AHN using immunohistochemistry and hippocampal protein expression via western blot.

Main Results:

• Trained mice showed reduced cell proliferation but increased immature neurons compared to controls.
• Enhanced AHN in Trained mice correlated with spatial reference memory performance.
• Trained animals exhibited increased hippocampal expression of BDNF, IGF-II, and phosphorylated CREB.

Conclusions:

• Appetitive spatial learning in the hole-board maze shifts AHN from proliferation to enhanced survival of young neurons.
• This task is a valuable model for studying AHN and hippocampal plasticity, mitigating stress-related confounds.
• The findings highlight the potential of appetitive learning to modulate neurogenesis and plasticity.